#include<math.h>
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<time.h>
#include<png.h>

typedef double f;
typedef int _;

png_image i;
png_bytep o[2];
f a, m[3], n[3], k[3], l[3], p[3], q[3];
_ B,e,A,T,R,I,C,E, *z[3];

_ g(_ u, char *v)
{
   return printf(u ? u - 1 ? "Error writing %s\n"
                           : "Error reading %s\n"
                   : "%s <input.png> <output1.png> <output2.png>\n",
                 v);
}

f r(f v)
{
   return (f)rand() / RAND_MAX * v;
}

_ main(_ u, char **v)
{
   if( u - 4 )
      return g(0, *v);

   i.version = PNG_IMAGE_VERSION;
   if( png_image_begin_read_from_file(&i, v[1]) )
   {
      E = i.width;
      I = i.height;
      for(i.format = PNG_FORMAT_RGBA; e < 3;
          z[e++] = (_*)calloc(E + 3, sizeof(_)))
         if( e < 2 )
            o[e] = (png_bytep)malloc(B = E * I * 4);
      A = *o && o[1] &&
          *z && z[1] && z[2] &&
          png_image_finish_read(&i, NULL, *o, 0, NULL);
   }
   if( !A )
      return g(1, v[1]);

   srand(time(NULL));

   for(memcpy(o[1], *o, B); T < 3; k[T++] = r(44.0 / 7))
   {
      m[T] = cos(a = r(44.0 / 7)) * (l[T] = (r(40.0) + 6.0) / (E < I ? E : I));
      n[T] = sin(a) * l[T];

      p[T] = r(E);
      q[T] = r(I);
   }

   for(R = B = 0; R < I; R++)
      for(T = 0; T < E; T++, B++)
      {
         for(a = e = 3; e--;)
            a += sin(sizeof('c') > 1
                        ? T * m[e] + R * n[e] + k[e]
                        : hypot(T - p[e], R - q[e]) * l[e]);
         a /= 6;

         A = a * 255 + z[C = R % 3][T + 1] / 8;

         memset(o[A > 127] + B * 4, 0, 4);

         z[C][T + 1] = 0;

         z[C][T + 2] += A -= A > 127 ? 255 : 0;
         z[C++][T + 3] += A;
         z[C %= 3][T] += A;
         z[C][T + 1] += A;
         z[C++][T + 2] += A;
         z[C % 3][T + 1] += A;
      }

   for(e = 0; e < 2; e++)
      if( !png_image_write_to_file(&i, v[e + 2], 0, o[e], 0, NULL) )
         return g(2, v[e + 2]);
   return 0;
}